Norway security police raises threat level after Oslo bomb scare

OSLO, April 9 (Reuters) - The Norwegian police force on Sunday raised its national threat assessment following the discovery of an improvised explosive device in central Oslo late on Saturday, the police security service (PST) said.

A 17-year old Russian citizen is in police custody and is a suspect in the case, police added.

The risk of an attack in the coming months has been raised to "probable" from "possible", PST chief Benedicte Bjoernland told a new conference. (Reporting by Terje Solsvik and Camilla Knudsen; Editing by Hugh Lawson)